Functional fluid compositions



United States Patent 3,490,737 FUNCTIONAL FLUID COMPOSITIONS Carl W.Gieseking, St. Louis, Mo., Quentin E. Thompson, Belleville, Ill., andRichard W. Weiss, St. Louis, Mo., assignors to Monsanto Company, St.Louis, Mo., a corporation of Delaware No Drawing. Filed Aug. 26, 1966,Ser. No. 575,926 Int. Cl. Cm 1/08 US. Cl. 25225 10 Claims ABSTRACT OFTHE DISCLOSURE Compositions of the class which exhibit improvedresistance towards corrosion which are polyphenyl thioethers, mixedpolyphenyl ether-thioethers, phenylmercaptobiphenyls and mixedphenoxyphenyltnercaptobiphenyls having incorporated therein in acorrosion inhibiting amount a metal organic compound wherein the metalis selected from Group IIA metals, Group IIIA metals, Group IV-A metals,Group IIB metals, Group IV-B metals, Group VI-B metals, nickel andcobalt.

This invention relates to functional fluid compositions having theability to inhibit and control corrosion damage to mechanical members incontact with said compositions and more particularly to compositionscomprising a functional fluid and corrosion inhibiting amounts of ametal compound.

Many different types of materials have been utilized as functionalfluids and functional fluids are used in many different types ofapplications. Such fluids have been used as electronic coolants, atomicreactor coolants, diffusion pump fluids, synthetic lubricants, dampingfluids, bases for greases, force transmission fluids (hydraulic fluids),heat transfer fluids, die casting release agents in metal extrusionprocesses and as filter mediums for air conditioning systems. Because ofthe wide variety of applications and the varied conditions under whichfunctional fluids are utilized, the properties desired in a goodfunctional fluid necessarily vary with the particular application inwhich it is to be utilized with each individual application requiring afunctional fluid having a specific class of properties.

Of the foregoing the use of functional fluids as lubricants,particularly jet engine lubricants, has posed what is probably the mostdiflicult area of application. As the operating temperatures forlubricants have increased it has become exceedingly diflicult to findlubricants which properly function at engine temperatures for anysatisfactory length of time. Thus, the requirements of a jet enginelubricant are as follows: The fluid should possess adequatetemperature-viscosity properties and satisgood storage stability and benon-corrosive and nondamaging to metal mechanical members which are incontact with the fluid. Such fluids should, in addition, possessadequate temperature-viscosity properties and satisfactory lubricity,that is, the lubricants must not become too thin at the very hightemperatures to which they are subjected nor must they become too thickat lower temperatures and must at the same time be able to providelubricity over such range of temperatures. In addition, such lubricantsshould not form deposits which interfere with the proper operation of ajet engine.

As the speed and altitude of operation of jet enginecontaining vehiclesincreases, lubrication problems also increase because of increasedoperating temperatures and higher bearing pressures resulting from theincreased thrust needed to obtain high speeds and altitudes. As theservice conditions encountered become increasingly severe the usefullife of the functional fluid is shortened, one

of the factors being increased corrosion of mechanical members incontact with the functional fluid. In general, as the operatingrequirements of a jet engine are in' creased, engine temperaturesincrease and oil temperatures in the range of 600 F. and higher areencountered.

The useful life of any lubricant can be adjudged on the basis of manycriteria such as the extent of viscosity increase, the extent ofcorrosion to metal surfaces in contact with the lubricant and the extentof deposits. Those skilled in the art have found many ways to improvelubricants and to thus retard or prevent the effects which shorten theuseful life of a lubricant. Thus, it is a general practice to add smallamounts of other materials, or additives, to lubricants in order toaffect one or more of the properties of the base lubricant. It isdiflicult, however, especially as operating temperatures are increased,to find additives which will still perform the function for which theyare added and yet not inject other problems such as increasing enginedeposits.

A problem which exists in functional fluid systems is the control ofcorrosion of mechanical members in contact with the fluid. Thus,depending upon the application, a fluid contacts various metals as forexample, aluminum, copper, bronze and steel and many alloys, whichalloys utilize many types of metals in the alloy composition. Corrosionof mechanical members in contact with a functional fluid adverselyaffects (1) the mechanical members of a system in contact with the fluidand (2) the functional fluid itself. Thus, damage to mechanical membersin contact with a functional fluid results in alteration of the geometryof the mechanical members in contact with the fluid and the corrosionproducts resulting therefrom contaminate the fluid. The corrosionproducts can form deposits on the mechanical members in contact with thefluid as Well as being solubilized in the functional fluid. Certaincorrosion products in addition to forming deposits can promote oxidationby catalyzing the oxidation of a functional fluid, thereby promotingincreased sludge and deposit formation. Thus, deposits and insolubleproducts interfere With the proper lubrication of mechanical members ina functional fluid system and in addition can act as insulatingmaterials when such deposits and insoluble materials form on mechanicalmembers. When this insulating efrect occurs, the fluid does not acceptheat as readily from mechanical parts at temperatures higher than thefluid and as a consequence metal fatigue and pitting of mechanicalmembers can occur. In addition, as a consequence of the corrosion ofmechanical members, the close tolerances which are required for certainmechanical members are altered, which alteration can result in anexcessive rate of wear thereby causing premature removal and replacementof mechanical parts.

It has now been found that control and inhibition of corrosion damageand thus the useful life of functional fluids can be greatly extended,even under the severe conditions encountered in jet engines and otherdevices operating at temperatures of the order of 550 F. and higher, bythe addition to functional fluids of a metal compound,

said metal compound being selected from the group con wherein M isselected from the group consisting of Group IIA metals, Group IIIAmetals, Group IV-A metals,

3 Group II-B metals, Group IV-B metals, Group VI-B metals, nickel andcobalt, a is a number having a value of atleast one and b is a numberhaving a value of from 1 to the product of a times the valence of M.

The functional fluids, to which a metal compound is added to provide thecompositions of this invention, hereinafter referred to as base stocks,include, but are not limited to, polyphenyl thioethers, mixed polyphenylether-thioethers, mixed phenoxyphenylmercaptobiphenyls,phenylmercaptobiphenyls, any of the above-described base stocks in whichpart or all of the cyclic rings represented by phenyl and pheylene arereplaced by a cyclic ring, other than phenyl or phenylene, such asalicyclic and heterocyclic, typical examples of which are cyclohexyl,thiophene and pyridene, and mixtures of the aforedescribed base stocks,provided that the number of sulfur atoms linking two or more of thephenyl, phenylene or cyclic rings is greater than one-third of the totalnumber of atoms represented by sulfur and oxygen linking the phenyl,phenylene and cyclic rings. It is contemplated that mixtures of theaforedescribed base stocks can contain major amounts of one base stockeven as high as 99% with the remainder being one or more base stocks.

Whereas the incorporation of any foreign element into a base stock canalter properties of a functional fluid, the concentration of metalcompounds represented by (A) and (B) in the base stock is adjusted interms of the particular system and the base stock which is utilized inthis system to provide functional fluid compositions of this inventionwhich contain additive amounts of a metal compound represented by (A)and (B) suflicient to inhibit and control corrosion damage of mechanicalmembers in contact with the functional fluid while not adverselyaffecting critical base stock properties. It has generally been foundthat the additive concentration of a metal compound represented by (A)and (B) for the base stocks described above is generally from about0.001 weight percent to about 10 weight percent, preferably from about0.01 weight percent to about 5 weight percent. Therefore, includedwithin the present invention are compositions comprising a base stockand a corrosion inhibiting amount of a metal compound represented by (A)and (B), that is, a metal compound represented by (A) and (B) is addedto the compositions at a concentration suflicient to inhibit and controlcorrosion damage.

The functional fluid compositions of this invention can be compounded inany manner known to those skilled in the art, as for example, by addinga metal compound represented by (A) and (B) to the base stock withstirring until a composition is obtained. It is also contemplated withinthe scope of this invention that compositions can be utilized whichcomprise a base stock and additive amounts of the metal compoundsrepresented by (A) and (B) in which the metal is dispersed, suspended orin contact with the base stock. Thus, the compositions of this inventioninclude the use of composition slurries such as the use of functionalfluid compositions of this invention as heat transfer fluids in whichthe additive can be present in other than a totally solubilized form. Inaddition, the metal compounds can be prepared in situ, that is, in thebase stocks as aforedescribed. It is also contemplated within the scopeof this invention that additive concentrates can be prepared such asadditive compositions containing from about to about 60% of the metalcompounds represented by (A) and (B) and the base stocks asaforedescribed.

Typical examples of Group II-A metals represented by M are beryllium,magnesium, calcium, strontium and barium. The preferred Group II-Ametals are magnesium, calcium and barium, although all the Group II-Ametals are contemplated within the scope of this invention.

Typical examples of Group III-A metals represented by M are aluminum,gallium and indium.

Typical examples of Group IV-A metals represented by M are tin and lead.The preferred Group IV-A metal is lead, although all Group IV-A metalsare contemplated within the scope of this invention.

Typical examples of Group IIB metals represented by M are zinc andcadmium. The preferred Group II-B metal is zinc, although all Group IIBmetals are contemplated within the scope of this invention.

Typical examples of Group IV-B metals represented by M are titanium andzirconium.

Typical examples of Group VI-B metals represented by M are chromium andmolybdenum. The preferred Group VI-B metal is chromium, although all theGroup VI-B metals are contemplated within the scope of this invention.

The anion portion of the compounds of this invention can be derived frommany sources and can be classified broadly as inorganic anions andhydrocarbon-containing anions. The term hydrocarbon-containing anion isherein defined to include hydrocarbons which, contain only carbon andhydrogen and also hydrocarbons which contain other elements in additionto carbon and hydro gen. The term hydrocarbons, which contain carbon andhydrogen as well as carbon, hydrogen and other elements, includeshydrocarbons which are completely saturated as well as hydrocarbonswhich have unsaturation. Thus, the term hydrocarbon-containing, inaddition to hydrocarbons containing only carbon and hydrogen, includeshydrocarbons containing one or more elements other than carbon andhydrogen, which elements can be substituted upon a hydrocarbon or canlink two or more hydrocarbon groups. It is also contemplated that ahydrocarbon-containing group can contain both substitution and linkageby one or more elements.

Typical examples of elements which the hydrocarboncontaininganions cancontain are boron, silicon, nitrogen, phosphorus, arsenic, oxygen,sulfur, selenium, tellurium, fluorine, chlorine and bromine. Typicalexamples of hydrocarbon-containing anions are acyloxy, substitutedacyloxy, aroyloxy and substituted aroyloxy, aryloxy and substitutedaryloxy, alkoxy, substituted alkoxy, alkyl, alkenyl, alkaryl, aralkyl,aryl, substituted alkyl, substituted alkenyl, substituted aryl, cyclicanion, that is (.carbonand hetero-groups); Group 1IIA non-metalhydrocarbon-containing anions such as hydrocarbon-containing boronanions; Group lV-A non-metal hydrocarbon-containing anions such ashydrocarbon-containing silicon anions; Group VA hydrocarbon anions, thatis, hydrocarbon-containing nitrogen anions, such as amido and thecorresponding substituted amido derivatives, hydrocarbon-containingphosphorus anions and hydrocarbon-containing arsenic anions; Group VI-Ahydrocarboncontaining anions, that is, hydrocarbon-containing sulfur,selenium and tellurium anions; and Group VII-A hydrocarbon-containinganions such as hydrocarbon-containing fluorine, chlorine, bromine andiodine anions. The term aryl as used above in the examples ofhydrocarboncontaining anions is defined to include mono-, diandpolynuclear aromatic hydrocarbons such as phenyl, naphthyl and anthryl.

Whereas all the above hydrocarbon-containing anions are contemplatedwithin the scope of this invention, it has been found that the preferredhydrocarbon-containing anions are those anions which contain an elementselected from oxygen, nitrogen and divalent sulfur, wherein the sulfuris contained in a heterocyclic ring or linking two aromatic rings orwhich contain two or more of'any combination of elements. The termhydrocarbon-containing anion is in addition defined to be that anionwhich does not adversely affect the performance of the metal compoundunder the conditions to which a functional fluid compositionincorporating metal compounds represented by (A) and (B) is subjected.Thus, for example, when a hydrocarbon-containing anion contains elementsas described above, as for example, halogen or sulfur other thandivalent sulfur as defined above in the preferred anions, such elementsshould be non-interfering with respect to the performance of the metalcompound in a functional fluid such that it will not completely nullifythe performance and activity of the metal compound under such operatingconditions and in the particular fluid system to which the functionalfluid composition is subjected.

The hydrocarbon-containing anions can be defined by the number of carbonatoms present in the anion per equivalent weight of metal represented byM wherein M has the same significance as aforedescribed. While there isno lower limit as to the number of carbon atoms or other elements thatcan be present in the anion portion, there is a preferred upper limitwhich is based upon the practical problem of obtaining a concentrationof M incorporated into a fluid without adversely affecting other fluidproperties. Thus, in general, it has been found that the preferred upperlimit with respect to the number of carbon atoms present per equivalentweight of M is generally up to about 60 carbon atoms per equivalentweight of M and even more preferably up to about 48 carbon atoms perequivalent weight of M. Thus, anions which contain more than oneequivalent of M attached to a given anion, that is, b is greater than a,would have a preferred upper carbon atom limitation for the anion, whichlimitation is obtained by multiplying the number of equivalents of Mattached to the anion times 60. The hydrocarbon-containing anions inaddition to the above can be defined by the number of elements otherthan carbon and hydrogen which are present per equivalent of metalrepresented by M wherein M has its aforedescribed significance. Thus,for hydrocarbon-containing anions containing oxygen, nitrogen ordivalent sulfur wherein the divalent sulfur is contained in aheterocyclic ring or linking two aromatic rings, or combinations of theabove elements, the number of elements which can be present perequivalent of M is as a preferred upper limit about 20 elements per oneequivalent of M and more preferably is an upper limit of about elementsper equivalent of metal represented by M. With respect to thehydrocarboncontaining anions which contain elements other than or inaddition to oxygen, nitrogen and divalent sulfur wherein the divalentsulfur forms part of a heterocyclic ring or links two aromatic rings,the preferred upper limit of the number of these other elements presentper equivalent of M is up to about 5 per equivalent of M and morepreferably up to about one element per equivalent of M.

It is also contemplated within the scope of this invention that theabove-described anion of the metal compounds can contain any combinationof the aforedescribed anions which are linked together to form oneanion. Thus, for example, there can be present in one anion acyloxy,alkoxy and hydrocarbon-containing silicon anions. As another example,there can be contained in one anion alkoxy and a hydrocarbon-containingphosphorus anion.

Typical examples of inorganic anions are nitrite, nitrate, cyanate,thiocyanate, carbonate, phosphate, borate, hydride, oxides, hydroxideand the like.

The inorganic anions that are preferred are those anions which cannot bederived from strong acids.

Typical examples of Grou III-A non-metal hydrocarbon-containing anionsare diethyl-p-hydroxybenzene boronic acid, p-hydroxyphenyl diphenylboroxin, m-hydroxy phenyldiphenyl boroxin,(p-hydroxyphenoxyphenyl)diphenyl boroxin and p-carboxyphenyl, ditolylboroxin and (p hydroxyphenoxyphenyl) di(phenoxyphenyl) boroxin.

Group IV-A non-metal hydrocarbon-containing anions can be derived, forexample, from silicon. Typical examples of these compounds arep-triphenyl silyl benzoic acid, p-(triphenyl silyl) propionic acid,p-hydroxyphenyl, pentaethyl disiloxane, triethyl silyl benzoic acid,4,4- (tetramethyl disiloxanylene) dibenzoic acid andp-hydroxyphenyltriphenyl silicate.

It is also contemplated that the above Group IV-A hydrocarbon-containinganions can be derived from polymeric compounds. Typical examples of suchpolymeric compounds are the methyl polysiloxanes, ethyl polysiloxanes,phenyl-methyl polysiloxanes which have been reacted with an unsaturatedacid such as acrylic or methacrylic acid to produce a graft polymer,that is, the acrylic or methacrylic acid is reacted with, for example,one of the methyl or ethyl groups.

Group V-A hydrocarbon-containing anions can be derived from, forexample, arsenic and phosphorus com pounds. Typical example of thephosphorus compounds which can be utilized to form the phosphorushydrocarbon-containing anions include the hydrocarbon-containing estersand amides of an acid of phosphorus, which include, by example,phosphoric acids, thiophosphoric acids, phosphinic acids, thiophosphinicacids, phosphonic acids, thiophosphonic acids and the like. Typicalexamples of hydrocrbon-containing phosphoric acid derivatives aredialkyl phosphoric acids, dialkyl-dithiophosphoric acids, dicyclohexylphosphoric acids, dimethylcyclohexyl phosphoric acids, di-Z-phenylhexylphosphoric acids, diphenyl phosphoric acids and di-n-dodecylphenylphosphoric acids.

The amido anions can be derived from various nitrogen-containingcompounds among which are amines. Typical amines which can be utilizedto prepare the amido anions are dimethylaminoethylamine,dimethylaminopropylamine, dimethylaminobutylamine,dimethylaminoheptylamine, diethylaminopropylamine,dihexylaminoarylamine, didodecylaminopropylamine,dioctyldecylpropylamine, N octadecyl N dodecylaminopropylamine,tetrahydropyrrole and the like. In addition, carbamic and dithiocarbamicacid compounds can be utilized to prepare metal compounds represented by(A) and (B).

Typical examples of Group VIA hydrocarbon-containing anions are thehydrocarbon sulfur-containing anions. These anions can be derived, forexample, from mercaptans and sulfonic acids, among which are thiophenol,dodecyl mercaptan, decyl mercaptan, octadecyl mercaptan, dialkylbenzenesulfonic acids and wax sulfonic acids derived from the sulfonation ofhigh molecular weight aliphatic materials.

The Group VIIA hydrocarbon-containing anions are anions which contain,for example, fluorine, chlorine, bromine or iodine. It is alsocontemplated that any of the aforedescribed anions can be substitutedwith Group VII-A elements.

The metal compounds represented by (A) and (B) can also be derived fromorgano-metallic compounds where the anion portion can be alkyl,substituted alkyl, aryl and substituted aryl, alkenyl and substitutedalkenyl. These compounds are commonly referred to as organometalliccompounds as there is bonding between the metal and carbon. Typicalexamples of these compounds are di(p-octylphenyl)zinc anddi(octadecyl)zinc.

While the aforedescribed anions are effective and contemplated withinthe scope of this invention as corrosion inhibitors, it has also beenfound that those hydrocarbon anions containing only carbon, hydrogen,oxygen, nitro gen and divalent sulfur which is contained in a heterocyclic ring or bound to two aromatic rings are more effective in alsoinhibiting and controlling corrosion damage to mechanical members incontact with a functional fluid. Thus, the preferred anions of thisinvention are, for example, acyloxy, substituted acyloxy, aroyloxy,substituted aroyloxy, aroxy, substituted aroxy, alkoxy, substitutedalkoxy, and substituted and unsubstituted carbonyloxy and oxyheterocyclic groups containing from 1 to 4 hetero atoms selected fromoxygen, sulfur and nitrogen and containing from 4 to 10 atoms in theheterocyclic ring.

Typical examples of metal acyloxy, substituted acyloxy, aroyloxy,substituted aroyloxy compounds, and

substituted and unsubstituted carbonyloxy heterocyclic groups are metalacetate, metal propionate, metal cyclohexanoate, metal neodecanoate,metal neotridecanoate, metal n-tetradecanoate, metal oleate, metalbitartrate, tetra-metal ethylenediamine tetra-acetate, dimetalethylenediamine tetra-acetic acid, dimetal ethylenediamine diacetate,metal ethylenediamine diacetic acid, tri-metal nitrilotriacetate, metalnitrilotriacetic acid, metal benzoate, metal salicylate, metalacetosalicylate, metal biphthalate, metal o-phenoxybenzoate, metalm-phenoxybenzoate, metal 1,1,3-trimethyl-2-keto valerate, metal phenylazobenzoate, metal m-phenyl azobenzoate, metal p-phcnyl azobenzoate,metal S-(m-nitrophenyl azo) salicylate, metal phenylacetate, metalbenzilate and metal pyrrolidinc.

In addition, the acyloxy, substituted acyloxy, aroyloxy, substitutedaroyl anions, substituted and unsubstituted carbonyloxy heterocyclicgroups can be derived from carboxylic acids, typical examples of whichare:

(A) ALIPHATIC MONOCARBOXYLIC ACIDS Formic acid, butyric acid, isobutyricacid, nitroisobutyric acid, valeric acid, isovaleric acid, hexanoicacid, heptanoic acid, Z-ethylhexanoic acid, nonanoic acid, decanoicacid, dodecanoic acid, undecanoic acid, hexadecanoic acid, heptadecanoicacid, octadecanoic acid, eicosanoic acid, docosanic acid, triacontanoicacid, butenic acid, pentenic acid, hexenic acid, teracrylic acid,hypogeic acid, elaidic acid, linoleic acid, ut-elostearic acid,alinolenic acid, acrylic acid, methacrylic acid, crotonic acid,isocrotonic acid, 3-butenoic acid, angelic acid, senecioic acid,hydrosorbic acid, sorbic acid and 4-tetradecenoic acid.

(B) ALICYCLIC MONOCARBOXYLIC ACIDS Cyclopropanecarboxylic acid,cyclopentanecarboxylic acid, hydrocarpic acid, chaulmoogric acid,naphthenic acid, 2,3,4,5-tetrahydrobenzoic acid andcyclodecanecarboxylic acid.

(C) AROMATIC MONOCARBOXYLIC ACIDS l-naphthoic acid, 2-naphthoic acid,o-toluic acid, mtoluic acid, p-toluic acid, o-nitrobenzoic acid,m-nitrobenzoic acid, p-nitrobenzoic acid, 2,3-dinitrobenzoic acid,m-hydroxybenzoic acid, p-hydroxybenzoic acid, gallic acid, anisic acidand B-phenylpropionic acid.

(D) HETEROCYCLIC MONOCARBOXYLIC ACIDS Picolinic acid, nicotinic acid,furylacrylic acid, piperic acid, indoxylic acid, 3-indoleacetic acid,cinchoninic acid, furoic acid, Z-thiophenecarboxylic acid,2-pyrrolecarboxylic acid, 9-acridancarboxylic acid, quinaldic acid,pyrazionic acid and antipyric acid.

(E) ALIPHATIC POLYCARBOXYLIC ACIDS Oxalic acid, malonic acid, succinicacid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaicacid, sebacic acid, brassylic acid, thapsic acid, maleic acid, fumaricacid, glutaconic acid, citraconic acid, itaconic acid, ethidenemalonicacid, mesaconic acid, allylmalonic acid, allylsuccinic acid, teraconicacid, xeronic acid, cetylmalonic acid, pyromellitic and trimelliticacid.

It is also contemplated herein to employ dimeric and trimericpolycarboxylic acids. When two like or unlike molecules of apolyethenoid monocarboxylic fatty acid condense to form a dicarboxylicacid, the product by definition is a dimer acid, or the carboxylic acidis said to be dimerized. In general, the dimer acids suitable for use inthis invention are produced by the condensation of two l or unlikeunsaturated aliphatic monocarboxylic acids having between about 16 andabout 18 carbon atoms per molecule, examples of which comprise A9,1l-hexadecadienoic acid A9,12-heptadecadienoic acid A8,12-octadecadienoicacid A9,ll-octadecadienoic acid A9,12-octadecadienoic acid (linoleicacid) A9,13-octadecadienoic acid A9,11,13-octadecatrienoic acidA9,l2,l5-octadecatrienoic acid(linolenic acid) It is also contemplatedwithin the scope of this invention that the polycarboxylic acids can beutilized to prepare partial or complete metal compounds, that is, when apartial metal compound is formed the remaining available carboxylic acidgroups can be reacted with other compounds, such as alcohols to formesters and amines to form amides or imides. It is also contemplated thatthe above carboxylic acid derivatives which contain other substituentswhich themselves can form a metal compound, such as hydroxy-substitutedcarboxylic acids can be utilized to prepare a partial or complete metalcompound. In addition, as for example, in the case where the anion is ahydroxy-substituted carboxylic acid, the metal M can be attached to theanion through the hydroxyl group and in such a case the carboxylic acidgroup can be blocked or hindered. In addition, a metal enolate can beformed from certain carbonyl-containing compounds, such as acetylacetone and such metal enolates are included within the scope of thisinvention.

Typical examples of metal alkoxides and aroxides are metal phenate,metal benzylate, metal diphenyl methoxide, metal triphenyl methoxide,metal lauryl methoxide, metal butyl methoxide and metalm,m-phenoxyphenoxyphenate.

It is also contemplated within the scope of this invention that thecarboxy group in the aforedescribed carboxylic acids which can be usedto prepare hydrocarboncontaining anions can be partially or totallyreplaced by a hydroxyl group and such compounds in turn can be utilizedto prepare metal compounds as represented by (A) and (B).

Typical examples of unsubstituted and substituted aroXy-, alkoxyandoxyheterocyclic groups from which the metal compounds represented by (A)and (B) can be derived are methyl, ethyl, propyl, n-butyl and tert-butylalcohols, isoamyl alcohol, cyclohexanol, lauryl alcohol, benzyl alcohol,cetyl alcohol, stearyl alcohol, phenol, o-, mand p-cresol, nitrophenol,gluaiacol, saligenin, thymol, o-, mand p-hydroxy acetophenone, o, mandp-hydroxy diphenyl, o-, mand p-cyclohexyl phenol, catechol, resorcinol,pyrogallol, o-, mand p-aminophenol, aand {3- naphthol,8-octyl-fl-naphthol, 6-dodecyl-tx-naphthol, 3,5,5- dimethyl-N-hexylphenol, N-decyl phenol, aceto phenol, nonyl phenol, alkaryl substitutedphenols, alkyl resorcinol, octyl catechol, thiophene-3-ol,2,3-quinoxaline diol, triisobutyl pyrogallol, 2-pyridinol,2,6-di-sec-butyl-pamino phenol, 4-N,N-dibutylaminomethyl-2,6-di-secbutyl phenol, o-, mand p-phenoxy phenols, 0-, m-,p- [(o-, m-, p-phenoxy)phenoxy1phenols, hydroxy quinolines, such asZ-hydroxy quinoline, 3-hydroxy quinoline, 6-hydroxy quinoline, 7-hydroxyquinoline and S-hydroxy quinoline.

It is also contemplated that polymeric compounds can be utilized toprepare the metal compounds represented by (A) and (B) in which part orall of the available sites are attached to a metal to form a metalcompound. A site is defined as a group such as hydroxyl or carboxylwhich is capable of uniting with a metal cation to form a metalcompound. Typical examples of such polymeric compounds are copolymers oflauryl methacrylate and acrylic acid copolymers of isooctyl acrylate andmethacrylic acid, polymers prepared from esters of acrylic acid andmethacrylic acid, polyesters and hydroxy-substituted polyphenyleneoxides. The compounds and mixtures of compounds which can be utilized toprepare the anions can contain many sites which can be attached to themetal. However, the metal can be attached to less than the total numberof available sites and the use of such metal compounds are contemplatedwithin the scope of this invention.

It is also contemplated within the scope of this inven# tion that thecompounds represented by (A) and (B) can contain two or more metalsrepresented by M. Typical examples of compounds containing a metalrepresented by M which can be interacted with the same or differentmetal represented by M to form a compound represented by (A) and (B)having two or more Ms are tin and lead hydrocarbon-containing compounds,such as p-triphenyl stannyl benzoic acid, p-hydroxyphenyl pentaphenylditin, m-hydroxybenzyl-tribenzyl lead, p-trimethyl plumbyl benzoic acidand phenyl plumbonic acid.

It is also contemplated within the scope of this invention that theanion portion can impart other properties to the functional fluidcompositions. Typical examples of such other properties which can beimparted are adjustment of viscosity, antifoam and lubricity. As anexample of imparting an additional property by an anion, a metal anionrepresented by (A) and (B) in which the anion is derived from apolysiloxane can impart antifoam properties. In addition, a metalcompound in which the anion is derived from a polymer such as amethacrylic acid ester polymer can alter the viscosity properties of afunctional fluid. As a further example, the metal anions in which theanion is derived from a hydrocarbon phosphorus-containing anion canirnpart. lubricity and load carrying ability to a functional fluidcomposition.

Examples of base stocks which are suitable as base stocks of thisinvention are represented by the structure wherein A, A A and A are eacha chalkogen selected from oxygen and sulfur, X, X X X and X each areselected from the group consisting of hydrogen, alkyl, hal-oalkyl,halogen, phenyl, alkaryl, hydro-xyl, alkoxy, aralkyl and substitutedaralkyl; w, y and z are whole numbers each having a value of to 8; c isa whole number having a value of from 1 to 4; d is a whole number havinga value of from 1 to and e is a whole number having a value of 0 to 1provided that when e is 0, y can have a value of l to 2 and providedthat the phenyl and phenylene groups in the aforedescribed base stockscan be partially or totally replaced with a cyclic group other than aphenyl or phenylene group, such as alicyclic or heterocyclic such asthiophene and pyridene, and provided that the number of sulfur atomslinking two or more of the phenyl, phenylene or cyclic rings is greaterthan one-third of the total number of hetero atoms represented by sulfurand oxygen linking the phenyl, phenylene or cyclic rings. Typicalexamples of such base stocks are polyphenyl thioethers and mixturesthereof, mixed polyphenyl ether-thioether compounds in which at leastone of the chalkogens represented by A, A A and A is dissimilar withrespect to any one of the other chalkogens, phenylmercaptobiphenyls,mixed phenoxyphenylmercaptobiphenyls and mixtures thereof.

10 Typical examples of polyphenyl thioethers, that is, when A, A A and Aare sulfur and a has a value of l are o-bis (phenylmercapto benzene,

m-bis phenylmercapto benzene,

bis (m-phenylmercaptophenyl sulfide,

m-phenylmercaptophenylp-phenylmercaptophenyl sulfide,

the trisphenylmercaptobenzenes,

such as 1,2,4-trisphenylmercaptobenzene,

m-bis p-phenylmercaptophenylmercapto benzene,

m-bis (m-phenylmercaptophenylmercapto benzene,

bis [mm-phenylmercaptophenylmercapto phenyl] sulfide,

mm-chlorophenylmercapto) m-phenylmercaptobenzene,

m-chlorodiphenyl sulfide,

bis(o-phenylmercaptophenyl) sulfide,

m-bis rn-phenylmercaptophenylmercapto) benzene,

1,2,3-tris (phenylmercapto benzene,

o-bis (o-phenylrnercaptophenylmercapto benzene,

m-bis (p-phenylmercaptophenylmercapto benzene and mixtures thereof.

Typical examples of phenylmercaptobiphenyls, that is, Where e has avalue of 0 and A, A A and A are sulfur are3,3'-bis(phenylmercapto)biphenyl, 0-, mand pphenylmercaptobiphenyl, 3,4phenylmercaptobiphenyl, 3,2-diphenylmercaptobiphenyl,m-chloro-phenylmercapto- 3phenylmercaptobiphenyl and mixtures thereof.

Typical examples of mixed polyphenyl ether-thioethers, that is, where 2has a value of l and at least one of the chalkogens represented by A A Aand A is dissimilar with respect to any other chalkogen provided thatthe number of chalkogens represented by A, A A and A is greater thanone-third sulfur are 1,2-phenylmercapto-3-bis (phenoxy) benzene,

2-phenylmercapto-4'-pl1enoxydiphenyl sulfide,

2-phenoxy-3'-phenylmercaptodiphenyl sulfide,

2,2'-bis- (phenylmercapto) di-phenyl ether,

3,4'-bis( rn-tolylmercapto) diphenyl ether,

3,3 -bis (xylylmercapto diphenyl ether,

3 ,4-bis m-isopropylphenylmercapto diphenyl ether,

3 ,4'-bis ptert-butylphenylmercapto) diphenyl ether,

3 ,3-bis m-chlorophenylmercapto diphenyl ether,

3 ,3 '-}bis m-trifluoromethylphenylmercapto diphenyl et er,

3 ,4-}bis (m-perfiuorobutylphenylmercapto) diphenyl et er,

2-m-tolyloxy-2-phenylmercaptodiphenyl sulfide,

m-phenylmercaptodiphenyl ether,

3 ,3 -bis (phenylmercapto diphenyl ether,

3- phenoxy-3 '-phenylmercaptodipheny1 sulfide,

3 ,4'-bis (phenylmercapto diphenyl ether,

In-bis m-phenylmercaptophenoxy) benzene,

3-pheny1mercapto-3 (m-phenylmercaptophenylmercapto) diphenyl ether andmixtures thereof.

Typical examples of mixed phenoxy-phenylmercaptobiphenyl, that is, Wheree has a value of O and one of the chalkogens represented by A, A A and Ais dissimilar with respect to any other chalkogen provided that thenumber of chalkogens represented by A, A A and A is greater thanone-third sulfur are phenylmercaptophenoxybiphenyl,o-phenylmercaptophenyl-m-phenoxyphenoxybiphenyl and mixtures thereof.

It is also contemplated within the scope of this invention that theaforedescribed base stocks can be blended together to provide mixturescomprising two or more of the above base stocks. A typical mixture of apolyphenyl thioether and a mixed polyphenyl ether-thioether is one whichcontains by weight from about 45% to about 55% m-phenoxyphenylm-phenylmercaptophenyl sulfide, from about 25% to about 35%bis(m-phenylmercaptophenyl) sulfide and from about 18% to about 25%bis(m-phenylmercaptophenyl) ether. Particularly useful mixtures arethose containing the above mixtures and m-bis(phenylmercapto)benzene isabout equal weight proportions. Typical examples of mixtures containingpolyphenyl thioethers, mixed polyphenyl ether-thioether and halogenatedpolyphenyl ethers which are suitable as lubricants under hightemperature conditions are as follows in weight percent:

It is also contemplated that any of the individual base stocks asdescribed above or mixtures thereof in admixture with additives of thisinvention can also be utilized to provide compositions of thisinvention.

In order to demonstrate the outstanding properties of a composition ofthis invention, various metal salts were blended into a base stock andthe resulting functional fluid composition evaluated for control ofmetal corrosion. One of the major bench scale methods used for measuringthe control of corrosion of a lubricant composition is a procedure givenin Federal Test Method 791, Method No. 5308 according to which thelubricant com position to be tested is heated at a specified temperature(500 F.) in the presence of certain metals and oxygen and the viscosityincrease of the lubricant is determined. Information as to thecorrosivity of a lubricant to metals and the degree of sludge anddeposit formation is determined.

In Table I, Examples 1 through 14, the compounds represented by (A) and(B) were tested in a base stock which was a mixture comprising a 3-ringpolyphenyl thioet'her, a 4-ring polyphenyl thioether and a mixedpolyphenyl ether-thioether containing a total number of sulfur atomslinking the phenyl and phenylene rings which was greater than one-thirdof the total number of sulfur and oxygen atoms linking the phenyl andphenylene rings. The temperature of the test was 500 F. and an air rateof 5 liters per hour was used. The duration of the test was 48 hours.The metal specimens that were used as specified in said procedure weresteel, copper, silver, titanium, magnesium alloy and aluminum alloy. Anegative sign on the copper and silver loss indicates that metal waslost.

TABLE I Net Change Concentrain Metal, tion, percent rug/cm.

EX. Additive in No. Metal Salt Base Stock On Ag Neat 0. 00 2. 13 0. 72

Magnesium benzoate 0. 1 O. 38 O. 07

Calcium m-phenoxybenzoate. 0. 1 -1. 97 0. 13

Barium m-phenoxybenzoate 0. 1 1. 18 O. 13

Aluminum benzoate 0. 1 O. 71 O. 27

Lead benzoate 0.2 0. 22 --0. 19 7 do 0.025 O. 21 0. 19 8- Lead hydroxidemonobenzoate 0. 1 O. 32 O. 13 9. Lead m-phenoxybenzoate 0. 2 0. 61 O. 1610 Zinc benzoate 0. 1 O. 49 0. 16 11 Zinc m-phen0xybenz0ate 0. 1 O. 290. 13 12 Zirconium benzoate 0. 1 -1. 59 O. 24 13 Chromium bcnzoate 0. 10. 64 O. 39 14- Nickel benzoate 0. 1 O. 93 -0. 17

The data in the previous examples demonstrate the significant inhibitionof corosion damage obtained by the functional fluid compositions of thisinvention which have incorporated therein the metal compoundsrepresented by (A) and (B). In addition the critical physical propertiesand performance characteristics, such as lubricity, fire resistance andviscosity, were not adversely affected, an important consideration sincea base stock is selected for a given fluid system because of itsphysical properties and characteristics and critical deviations fromthese properties and characteristics can bring about inferior fluidperformance. In particular, Table I demonstrates that the incorporationof a metal compound represented by (A) and (B) can bring about areduction in both copper and silver corrosion as evidenced by thereduction in weight loss of the metal specimens. In many of theexamples, the percent improvement in the control of copper and silvercorrosion was in the order of and in some cases higher. The control andinhibition of copper corrosion is of particular importance sincemechanical members in contact with the fluid which are corroded canexhibit pitting and loss of metal, which loss of metal alters thegeometry and close tolerances which are necessary for the properoperation of a particular system. The control of copper corrosionutilizing the functional fluid compositions of this invention extend thelife of the actual fluid system and in addition the functional fluiditself.

In addition to control of corrosion to mechanical members in contactwith the fluid, the incorporation of the metal compound into a basestock inhibits and controls damage to the fluid itself. The inhibitionand control of corrosion damage prevents corrosion products fromcontaminating the fluid which contamination product can cause anincreased rate of oxidation of the fluid. The metal salts which canresult from corrosion can act as pro-oxidants thereby increasing fluiddamage which manifests itself in numerous ways, among which areviscosity change, increase acid number, formation of insolublematerials, increased reactivity and discoloration. In a fluid system theparticular properties of a fluid have to be maintained in order tocontinue useful operation of the particular system in which the fluidsare employed. Thus, changes in viscosity can be produced by fluiddegradation whereby polymeric products with high molecular weights areproduced in the system. Such high molecular weight products often becomeinsoluble in the particular base stock which results in theprecipitation or sludging of the insoluble material. Such precipitationand sludging plugs filters and deposits on moving parts which have to belubricated by the fluid thereby causing inadequate lubrication.Increased chemical reactivity is observed on fluid degradation as wellas a build-up of the acid number of the fluid. Such increased chemicalreactivity and high acid number allows the particular system whichincorp rates the fluid to be chemically attacked by the fluid therebycausing additional pitting, wear and alterations of the close tolerancesof the mechanical members of said fluid. Thus, premature overhaul ofmechanical parts can be a direct consequence of fluid degradation. Thus,it is of particular importance that corrosion damage of mechanicalmembers in contact with fluid be inhibited and controlled in order toprevent damage to mechanical members and in addition fluid degradationwhich can be a direct consequence of contamination of a fluid withcorrosion products.

As a result of the improved control of corrosion by functional fluidswhich incorporate the metal compounds of this invention, lubrication ofgas turbine engines is obtained over extended periods of time. Thus,this invention relates to a novel method of lubricating gas turbineengines which comprises maintaining on the bearings and other points ofwear a lubricating amount of a composition of this invention.

As a result of the excellent inhibition and control of damage utilizingthe functional fluid composition of this invention, improved hydraulicpressure devices can be prepared in accordance with this invention whichcomprise in combination a fluid chamber and an actuating fluidcomposition in said chamber, said fluid comprising a mixture of one ormore of the base stocks hereinbefore described and a minor amount,sufficient to inhibit and control corrosion damage, of the additivecomposition of this invention. In such a system, the parts which are solubricated include the frictional surfaces of the source of power,namely the pump, valves, operating pistons and cylinders, fluid motors,and in some cases, for machine tools, the ways, tables and slides. Thehydraulic system may be of either the constant-volume of thevariablevolume type of system.

The pumps may be of various types, including centrifugal pumps, jetpumps, turbine vane, liquid piston gas compressors, piston-type pump,more particularly the var able-stroke piston pump, thevariable-discharge or variable displacement piston pump, radial-pistonpump, axialpiston pump, in which a pivoted cylinder block is adjusted atvarious angles with the piston assembly, for example, the Vickersaxial-piston pump, or in which the mechanism which drives the pistons isset at an angle adjustable with the cylinder block; gear-type pump,which may be spur, helical or herringbone gears, variations of internalgears, or a screw pump; or vane pumps. The valves may be stop valves,reversing valves, pilot valves, throttling valves, sequence valves,relief valves, servo valves, non-return valves, poppet valves orunloading valves. Fluid motors are usually constantor variabledischargepiston pumps caused to rotate by the pressure of the hydraulic fluid ofthe system with the power supplied by the pump power source. Such ahydraulic motor may be used in connection with a variable-discharge pumpto form a variable-speed transmission. It is, there fore, especiallyimportant that the frictional parts of the fluid system which arelubricated by the functional fluid be protected from damage. Thus,damage brings about seizure of frictional parts, excessive wear andpremature replacement of parts.

In addition, due to the excellent physical properties of thecompositions of this invention having incorporated therein a metalcompound represented by (A) and (B), heat transfer systems can bedeveloped wherein a liquid heat exchange medium is utilized to exchangeheat with another material wherein said material is at a giventemperature. Thus, the function of the liquid heat exchange medium canbe any one or a combination of the following: transfer heat, accept heatand maintain a material at a given temperature.

The fluid compositions of this invention when utilized as a functionalfluid can also contain one or more dyes, pour point depressants, metaldeactivators, acid scavengers, antioxidants, defoamers in concentrationsufficient to impart antifoam properties, such as from about to about100 parts per million, viscosity index improvers such aspolyalkylacrylates, polyalkylmethacrylates, polycyclic polymers,polyurethanes, polyalkylene oxides, polyalkylene polymers, polyphenyleneoxides, polyesters, lubricity agents and the like.

It is also contemplated within the scope of this invention that the basestocks as aforedescribed can be utilized singly or as a fluidcomposition containing two or more base stocks in varying proportions.The base stocks can also contain other fluids which include, in additionto the functional fluids described above, fluids derived from coalproducts and synthetic oils, e.g., alkylene polymers (such as polymersof propylene, butylene, etc., and mixtures thereof), alkylene oxide-typepolymers (e.g., propylene oxide polymers) and derivatives, includingalkylene oxide polymers prepared by polymerizing the alkylene oxide inthe presence of water or alcohols, e.g., ethyl alcohol, alkylbenzenes(e.g., monoalkylbenzene such as dodecylbenzene, tetradecylbenzene,etc.), and dia'lkylbenzenes (e.g., n nonyl 2-ethylhexylbenzene);polyphenyls (e.g., biphenyls and terphenyls), halogenated benzene,halogenated lower alkylbenzene, halogenated biphenyls, halogenateddiphenyl ethers, trialkyl, phosphine oxides, diarylalkyl phosphonates,trialkyl phosphonates, aryldialkyl phosphonates, triaryl phosphonates,diand tri-carboxylic acid esters, such as di-Z-ethylhexyl adipate, di-2-ethylhexyl sebacate, polyesters, such as trimethylolpropane,pentaerythritol, dipentaerythritol esterified with acids such asbutyric, propionic, caproic and Z-ethylhexanoic and complex esters suchas are obtained by esterifying a dicarboxylic acid with a glycol and amonocarboxylicacid, and polyphenyl ethers, typical examples of which arebis(phenoxyphenyl) ethers, e.g., bis (mphenoxyphenyl) ether; the his(phenoxyphenoxy)benzenes, e.g., m bis(m-phenoxyphenoxy)benzene,m-bis(p-phenoxyphenoxy)benzene, o bis(o phenoxyphenoxy)benzene; thebis(phenoxyphenxyphenyl) ethers, e.g., bis[m- (m phenoxyphenoxy)phenyl]ether, bis[p (p-phenoxyphenoxy)phenyl] ether, m [(m-phenoxyphenoxy)(ophenoxyphenxy] ether and the bis(phenoxyphenoxyphenoxy) benzenes,e.g., m bis[m (m-phenoxyphenoxy) phenoxyJbenzene, p bis[p(m-phenoxyphenoxy)phenoxy]benzene, m bis[m (p-phenoxyphenoxy)phenoxy]benzene and 1,3,4-triphenoxybenzene. It is also contemplated thatmixtures of the polyphenyl ethers can be used. For example, mixtures ofpolyphenyl ethers in which the non-terminal phenylene rings (i.e., thoserings enclosed in the brackets in the above structural representation ofthe polyphenyl ethers contemplated) are linked through oxygen atoms inthe meta and para positions, have been found to be particularly suitableas lubricants because such mixtures possess lower solidification pointsand thus provide compositions having wider liquid ranges. Of themixtures having predominantly meta and para linkages, a preferredpolyphenyl ether mixture of this invention is the mixture of S-ringpolyphenyl ethers where the nonterminal phenylene rings are linkedthrough oxygen atoms in the meta and para positions and composed, byWeight, of about 65% m bis(mphenoxyphenoxy)benzene, 30% m [(mphenoxyphenoxy)(p-phenoxyphenoxy)]benzene and 5% mbis(p-phenoxyphenoxy)benzene. Such a mixture solidifies at about -10 F.whereas the the three components solidify individually at temperaturesabove the normal room temperatures.

Examples of substituted polyphenyl ethers are l-(pmethylphenoxy) 4phenoxybenzene, 2,4-diphenoxy-1- methylbenzene, bis [p (pmethylphenoxy)phenyl] ether, bis[p (p-tert-butylphenoxy)phenyl] etherand mixtures thereof. The aforedescribed fluids can be added in amountssuch that the final base stock has a total number of sulfur atomslinking the phenyl, phenylene and cyclic rings in the aforedescribedbase stocks, great-er than one-third of the total number of sulfur andoxy linkages linking the phenyl, phenylene and cyclic rings.

While this invention has been described with respect to various specificexamples and embodiments, it is to be understood that the invention isnot limited thereto and that it can be variously practiced within thescope of the following claims.

The embodiments of the invention in which an exclusive property orprivilege is claimed are defined as follows:

1. A composition comprising (A) a major amount of a base stock selectedfrom the group consisting of l) polyphenyl thioethers,

(2) mixed polyphenyl ether-thioethers,

(3) phenylmercaptobiphenyls,

(4) mixed phenoxyphenylmercaptobiphenyls and (5) mixtures of anycombination of (1), (2), (3) and (4), provided that the total number ofsulfur linkages in a mixed polyphenyl ether-thioether compound linkingthe aryl and arylene rings is greater than one-third of the sum of thetotal number of oxy and sulfur linkages linking the aryl and arylenerings; and

(B) a corrosion inhibiting amount of a material selected from the groupconsisting of (1) a metal compound represented by the structure whereinM is selected from the group consisting of Group II-A metals, GroupIII-A metals, Group lV-A metals, Group II-B metals, Group IV-B metals,Group VI-B metals, nickel and cobalt, a is a number having a value of atleast one and b is a number having a value of from 1 to the product of atimes the valence of M, anion is a member of the class consisting ofcarbonate, oxide, hydroxide, halide and hydrocarbon-containing anionsselected from the group consisting of acyloxy, aroyloxy, aroxy, alkoxy,and a carbonyloxy carbon-containing heterocyclic group having from 4 toatoms optionally interrupted by from 1 to 4 hetero atoms selected fromthe group consisting of oxygen, sulfur and nitrogen, and an oxycarbon-containing heterocyclic group having from 4 to 10 atomsoptionally interrupted by from 1 to 4 hetero atoms selected from thegroup consisting of oxygen, nitrogen and sulfur.

2. A composition of claim 1 wherein the metal compound contains from 1to about 60 carbon atoms per equivalent of metal.

3. A composition of claim 2 wherein the metal compound contains from 1to about 48 carbon atoms per equivalent of metal.

4. A composition of claim 3 wherein the anion is an aroxy group.

5. A composition of claim 3 wherein the anion is an alkoxy group.

6. A composition of claim 1 wherein M is selected from the groupconsisting of magnesium, calcium, barium, zirconium, nickel, zinc,cadmium and lead.

7. A composition of claim 2 wherein M is selected from the groupconsisting of magnesium, calcium, barium, zirconium, nickel, zinc,cadmium and lead.

8. A composition of claim 1 wherein M is selected from the groupconsisting of magnesium, calcium, barium,

zirconium, nickel, zinc, cadmium and lead and anion is carbonate, oxideor hydroxide.

9. A composition of claim 1 wherein the base stock is selected from thegroup consisting of unsubstituted polyphenyl thioethers, unsubstitutedmixed polyphenyl etherthioethers containing from 3 to 10 aromatic ringsand mixtures thereof.

10. A composition of claim 3 wherein the base stock is selected from thegroup consisting of unsubstituted polyphenyl thioethers, unsubstitutedmixed polyphenyl etherthioethers containing from 3 to 10 aromatic ringsand mixtures thereof.

References Cited UNITED STATES PATENTS 2,079,051 5/1937 Sullivan et a125225 2,125,961 8/1938 Shoemaker et al.

25233.6 XR 2,197,833 4/1940 Reiff 25242.7 2,335,017 11/1943 MCNab et a1.25242.7 XR 2,940,929 6/1960 Diamond 25233.6 3,065,173 11/1962 Blake eta1 25225 XR 3,096,375 7/1963 Campbell et al. 252 XR 3,163,603 12/1964 LeSuer 252336 3,198,734 8/1965 MorWay 25252 XR 3,236,773 2/ 1966 Stemniskiet al. 25252 XR 3,242,081 3/1966 McHHgh et al. 25246.4 XR 3,244,6274/1966 Smith et a1 25233.6 3,244,629 4/1966 Smith et a1 25246.43,268,445 8/1966 Ambrose et al. 25252 XR 3,290,249 12/1966 Wilson 25252XR 3,311,665 3/1967 Campbell et al. 25245 XR 3,314,887 4/ 1967 Carlson25242.7 3,321,529 5/1967 Campbell 25245 XR FOREIGN PATENTS 851,65110/1960 Great Britain.

DANIEL E. WYMAN, Primary Examiner I. VAUGHN, Assistant Examiner US. Cl.X.R.

